The 191V42-8 Power Source Kit consists of 2 x BL4050 40V Max XGT Li-ion 5.0 Ah batteries & a DC40RA/2 240V fast charger, supplied in a Makpac case. The MKP 5.0 Ah Power Source Kit is specially designed for use with 40V Max & 18V LXT products being used in continuous operation. The BL4050F is a 40V Max Li-ion XGT 5.0 Ah Battery, a new type of cell with increased water & drop impact resistance. Communication between the battery & charger, allows to read more detailed information on the battery usage history. The BL4050F communicates digitally between the battery & the tool & battery & the charger & is equipped with 4 LED battery fuel gauge with a check button & cooling system for maximum battery life. The average charging time for a BL4050F is Approx. 50 minutes. The 240V DC40RA 40V Max Fast Charger is designed for charging 40V Max Li-ion XGT batteries, equipped with raised & enlarged charging indicator status light for a more visible indication, selectable melody sound for notification of fully charged battery & has two cooling fans, one for the battery & one for the charging circuit. The DC40RA is capable of performing consecutive fast charges of batteries & is compatible with the Makita Interchangeable Adapter ADP10 (available separately) for charging Makita Li-ion LXT slide type batteries. DC40RA is wall mountable. The charging time for a BL4020 40V 2.0 Ah battery is Approx. 22 minutes, BL4025 40V 2.5 Ah battery is Approx. 28 minutes & a BL4040 40V 4.0 Ah battery is Approx. 45 minutes.